Modified conjugated diene polymer and method of producing the same and rubber composition

Abstract

A novel modified conjugated diene polymer is obtained by polymerizing a conjugated diene compound with a specified catalyst consisting of components (a)-(c) and then reacting with at least one specified compound selected from the group consisting of components (d)-(l), and has a content of cis-1,4-bond of not less than 85% and a ratio of weight average molecular weight to number average molecular weight of not more than 4. And also, a rubber composition comprises the modified conjugated diene polymer a rubber ingredient.

1. A terminal-modified conjugated diene polymer obtained by modifying or coupling a conjugated diene polymer with at least one compound selected from the group consisting of the following components (d), (e), and (f), and having a content of cis-1,4-bond in a conjugated diene portion of not less than 85% and a ratio of weight average molecular weight (Mw) to number average molecular weight (Mn) of not more than 4 as measured through a gel permeation chromatography:
 Component (d): a quinone compound;  
 Component (e): a thiazole compound; and  
 Component (f): a sulfenamide compound.  
 
     
     
       2. A terminal-modified conjugated diene polymer according to  claim 1 , wherein said ratio (Mw/Mn) is not more than 3.5. 
     
     
       3. A terminal-modified conjugated diene polymer according to  claim 1 , wherein said polymer has a content of 1,2-vinyl bond of not more than 2.5%. 
     
     
       4. A rubber composition comprising 20-120 parts by weight of carbon black based on 100 parts by weight of rubber ingredient consisting of 10-100% by weight of a terminal-modified conjugated diene polymer as claimed in any one of claims  1  and  2  to  3  and 90-0% by weight of at least one other rubber selected from the group consisting of natural rubber, synthetic isoprene rubber, butadiene rubber, styrene-butadiene rubber, ethylene-α-olefin copolymer rubber, ethylene-α-olefin-diene terpolymer rubber, acrylonitrile-butadiene copolymer rubber, chloroprene rubber and halogenated butyl rubber (provided that the modified conjugated diene rubber+the other rubber=100% by weight).